Are you seeing lightning flashes (and there is no thunderstorm)? Do you feel like you are constantly living in a tornado of dust?
You’re not losing it. Is may be merely a visual phenomenon.
If you have seen something moving across your field of vision, or you think you are seeing ants moving on the table, you could be experiencing floaters. A floater is a universal term for specks, threads or cobweb type images that you see drifting in your vision. Sometimes when you have floaters you will also notice a flash of light similar to a camera’s flash.
Eye flashes and floaters can be harmless, but they can also be a warning sign trouble is on its way.
What are floaters?
Floaters are formed in the vitreous – the gel-like substance in the back of your eye. When you age, the vitreous gel often shrinks in size, becoming a bit stringy, and flecks of collagen can come loose. As the name suggests they float in the gel as you move your eye around. Try as you might, it is difficult to follow a floater because as you move your eye, they drift with it.
Most often you can ignore floaters and get on with life. But sometimes they are big enough to affect your focus – particularly when reading.
What are flashes?
Eye flashes are caused when the retina – the thin film in the back of your eye is stimulated. When the retina is tugged or torn from the back of the eye it sends a signal along the optic nerve to the brain. When you see flashes it can mean the vitreous gel is pulling away from your retina. If the vitreous is abnormally sticky when it pulls away it can cause a retinal tear.
Flashes in your eyes are always serious and you need to get them checked out. If the flashes occur in both eyes and last for several minutes, you may be experiencing a migraine-type visual aura, postural hypotension, or suffering a stroke.
Danger ahead?
The shrinking vitreous can tug on the retina and pull away from it. Medically referred to as a posterior vitreous detachment (PVD), this is the most common cause of acute-onset floaters and flashes in one eye and doesn’t usually threaten vision. The prevalence increases with age, 24% of 50–59-year-old adults have experienced a PVD, rising to 87% for people over 80 years.
Sometimes flashes and floaters lead to vision loss. If the floaters and flashes are caused by a tear or detachment of your retina it is much more serious. A tear is painless but when left untreated fluid can seep under the retina causing it to detach. Without intervention, a retinal detachment will lead to vision loss and possibly, blindness.
To check for missing vision or blurred vision, cover each eye separately, and make sure you can see all four corners of your visual field. Patients with a retinal detachment often describe initially a cobweb in their vision that quickly progresses to a curtain coming down over their vision. This is a medical emergency and should be addressed immediately.
Risk factors
- 10-15% of people with symptoms of flashes and floaters develop a retinal tear
- Majority of retinal detachments occur between 50-60 years old
- A hole or tear in the retina will almost always develop into a detachment if left untreated
- Near-sightedness or myopia
- Any previous eye surgery or trauma
- Previous retinal detachment
- Diabetes
- Family history of retinal detachment
Will your eye floaters go away?
Floaters caused by a PVD don’t necessarily go away over time, but they do become less obvious. They can slowly sink and settle in the bottom of your eye out of your line of sight. Your brain will also start to ignore them over time.
Treatment for flashes and floaters
Most people don’t require treatment for eye floaters caused by a PVD. But if you are experiencing many annoying floaters that are impairing your vision then your eye doctor may recommend surgery. The vitreous (including the floaters) is removed and replaced with clear fluid – a procedure known as vitrectomy.
When your flashes and floaters are caused by a retinal tear or detachment urgent treatment is required. If there is a small tear or hole, then laser or cryotherapy can seal it and the visual prognosis is good. If the retina has detached surgery is required immediately.
If you notice a sudden onset of floaters or flashes seek advice from your eye doctor.
